Electrospinning in a controlled gaseous environment

• US 7,297,305 B2
• Filed: 04/08/2004
• Issued: 11/20/2007
• Est. Priority Date: 04/08/2004
• Status: Active Grant

• Current Assignee: Research Triangle Institute
• Original Assignee: Research Triangle Institute
• Inventors: Ensor, David S., Andrady, Anthony L.
• Primary Examiner(s): Tentoni; Leo B.
• Application Number:
  US10/819,945
• Publication Number:
  US 20050224999A1
• Time in Patent Office: 1,321 Days
• Field of Search: 264/10, 264/29.2, 264/465
• US Class Current: 264/465
• CPC Class Codes: D01D 5/0061 characterised by the electro-spinning apparatus
• CPC Class Codes: D01F 11/00 Chemical after-treatment of artificial filaments or the like during manufacture
• CPC Class Codes: H05B 6/62 Apparatus for specific applications
• CPC Class Codes: Y10T 428/249924 Noninterengaged fiber-containing paper-free web or sheet which is not of specified porosity
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber

Abstract

Apparatus and method for producing fibrous materials in which the apparatus includes an extrusion element configured to electrospin a substance from which the fibers are to be composed by an electric field extraction of the substance from a tip of the extrusion element, a collector disposed from the extrusion element and configured to collect the fibers, a chamber enclosing the collector and the extrusion element, and a control mechanism configured to control a gaseous environment in which the fibers are to be electrospun. The method includes providing a substance from which the fibers are to be composed to a tip of an extrusion element, applying an electric field to the extrusion element in a direction of the tip, controlling a gaseous environment about where the fibers are to be electrospun, and electrospinning the substance from the tip of the extrusion element by an electric field extraction of the substance from the tip into the controlled gaseous environment.

Claims

1. A method for producing fibers, comprising:

providing a substance from which the fibers are to be composed to a tip of an electrospinning element;

applying an electric field to the electrospinning element in a longitudinal direction of the electrospinning element;

controlling a gaseous environment about where the fibers are to be electrospun by introduction of a gaseous substance into a shroud extending from an interior wall of a chamber enclosing the electrospinning element, said shroud partially enclosing the electrospinning element; and

electrospinning the substance from the tip of the electrospinning element by an electric field extraction of the substance from the tip into the controlled gaseous environment.

2. The method of claim 1, wherein the controlling comprises:

flowing at least an electronegative gas through the shroud.

3. The method of claim 2, wherein the controlling comprises:

injecting at least one of CO₂, CO, SF₆, CF₄, N₂O, CCl₄, CCl₃F, and C₂Cl₂F₂ into the shroud.

4. The method of claim 1, wherein said electrospinning comprises:

electrospinning said substance in the electric field having a strength of 2,000-400,000 V/m.

5. The method of claim 1, wherein said electrospinning comprises:

electrospinning nanofibers.

6. The method of claim 1, further comprising:

introducing a vapor of a solvent into the gaseous environment.

7. The method of claim 6, wherein the introducing a vapor comprises:

introducing the vapor at a predetermined vapor pressure.

8. The method of claim 7, where the introducing comprises:

exposing the chamber to at least one of dimethyl formamide, methylene chloride, acetone, and water.

9. The method of claim 1, wherein the electrospinning compnses:

electrospinning polymeric fibers.

10. The method of claim 9, further comprising:

annealing said polymeric fibers to form carbon fibers.

11. The method of claim 1, wherein the electrospinning comprises:

electrospinning polymeric nanofibers.

12. The method of claim 11, further comprising:

annealing said polymeric nanofibers to form carbon nanofibers.

13. The method of,claim 1, wherein the providing a substance comprises:

providing as said substance a solvent in which a polymer is dissolved.

14. The method of claim 13, wherein the providing as said substance comprises:

providing at least one of dimethyl formamide, methylene chloride, acetone, and water.

15. The method of claim 1, further comprising:

injecting at least one of ions and energetic particles into the gaseous environment.

16. The method of claim 15, wherein the injecting at

least one of ions and energetic particles comprises:

generating the ions; and

injecting the generated ions into the gaseous environment.

17. The method of claim 16, wherein the injecting the generated ions comprises:

injecting the ions into a Rayleigh instability region downstream from the electrospinning element.

21. The method of claim 1, wherein the controlling comprises:

introducing a combination of gasses and vapors to the gaseous environment.

22. The method of claim 21, wherein the introducing comprises:

introducing at least one of electronegative gases and inert gases to the gaseous environment.

23. The method of claim 21, wherein the introducing comprises:

introducing solvent vapors to the gaseous environment.

24. The method of claim 1, wherein the controlling comprises:

introducing the gaseous substance through the shroud which extends along the longitudinal direction of the electrospinning element.

18. A method for producing fibers, comprising:

providing a substance from which the fibers are to be composed to a tip of an electrospinning element;

applying an electric field to the electrospinning element in a longitudinal direction of the electrospining element;

controlling a gaseous environment about where the fibers are to be electrospun to retard a solidification rate of the fibers by introduction of an organic solvent into the gaseous environment; and

electrospinning the substance from the tip of the electrospinning element by an electric field extraction of the substance from the tip into the controlled gaseous environment.

19. A method for producing fibers, comprising:

providing a substance from which the fibers are to be composed to a tip of an electrospinning element, said substance including a polymer dissolved in a solvent and said provision of the solvent to the tip providing a first source for introduction of the solvent into an electrospinning environment;

applying an electric field to the electrospinning element in a longitudinal direction of the electrospining element;

controlling the electrospinning environment about where the fibers are to be electrospun by introducing a vapor of the solvent into the electrospinning environment from a liquid pool in the electrospinning environment and thereby providing a second source for introduction of the solvent into the electrospinning environment; and

electrospinning the substance from the tip of the eleetrospinning element by an electric field extraction of the substance from the tip into the controlled electrospinning environment.

20. The method of claim 19, wherein providing comprises:

including in the substance from which the fibers are to be composed an organic solvent.